Metabolites regulating eye colour could impact retinal health: Study

According to a new study, researchers have found that altering the levels of metabolites in a pathway responsible for regulating eye colour might impact retinal health.

New Delhi: Altering the levels of metabolites in the Kynurenine pathway, responsible for regulating eye colour, has been found to impact retinal health, according to a new study in flies. The study conducted by Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG) in Germany investigated the classic Drosophila genes cinnabar, cardinal, white, and scarlet, named due to their role in eye colour pigmentation and in particular the formation of the brown pigment of the fly eye.

These genes encode components of the kynurenine pathway, a metabolic pathway responsible for regulating eye colour, among other various biological processes. Changes in this pathway can impact the health of the brain, including the retina. Metabolic pathways consist of a series of biochemical reactions in cells that convert a starting component into other products.

The scientists studied the role of these genes using flies as model, in whom this metabolic pathway is conserved. They used genetics, dietary changes, and biochemical analysis of metabolites to study different mutations of the fruit fly, Drosophila melanogaster. The researchers developed a biochemical analysis method, which allowed them to link levels of different metabolites of the pathway to retinal health.

They found, through this method, that absolute amounts as well as relative differences between the levels of 3-hydroxykynurenine (3OH-K), which is toxic to retina, and protective metabolites, such as Kynurenic Acid (KYNA), governed retinal degeneration. "We also fed two of these metabolites to normal (non-mutant) flies and found that 3OH-K enhanced stress-induced retinal damage, whereas KYNA protected the retina from stress-related damage," said Sarita Hebbar, one of the lead authors of the study.

Altering levels of the Kynurenine pathway metabolites, therefore, presented one of the means to improve retinal health. Further, the scientists were also able to demonstrate that the location of these metabolites in the cell, and thus their availability for further reactions, too was important for retinal health.

"The ratio of the various metabolites and the specific sites of their accumulation and activity should be taken into account in therapeutic strategies for diseases with impaired Kynurenine pathway function, observed in various neurodegenerative conditions," said Elisabeth Knust, who supervised the study. (PTI)